This item is usually set to the Misra Chapu Thaalam and Ragamalika (different Ragams or Tunes for different stanzas). But essentially the whole item is about one person, one theme. Each stanza can contain a different story or all of them put together The song ( saahityam) is usually separated into stanzas and between each stanza, you'll have a simple Korvai ( nritta steps). Shabdam is a Bharatanatyam Item in which the Expressions ( or Abhinaya) are introduced for the first time in the repertoire. So the total number of "Aksharams" (hits) make up one "Aavartanam" of a Thaalam. Each Thaalam comes in cycles of a number of beats, called an "Aavartanam" (आवर्तन ). In Carnatic Music, each pulse (every hit) is called "Aksharam" (अक्षर ) that are placed at equal intervals ( although each interval is capable of being divided into faster or slower Swaras). Each and every Thaalam has a structure, that is governed by the rules pertaining to it. Songs are set to a specific Thaalam or beat. Rhythm in Carnatic music changes for each composition. So if you get the chance to learn both, do learn them!) But it is noticed that those who learn both Carnatic Music and Bharatanatyam together have a better understanding of the system of Talam, Ragam, Emotions etc. ( Not all Bbharatanatyam dancers learn Carnatic Music. An understanding of the Talam System of Carnatic Music will ensure a wholesome learning of this art form. A Bharatanatyam dance is usually set to Carnatic Music and Carnatic Music is set to rhythmic pattern of beats known as Taalam. "Taalam" (तालं ) is a Sanskrit word that means "to clap". But messing up the Beats (Taal) will definitely mess up your performance and make people notice your mistakes. Even missing one beat in the Taal can be catastrophic! :-D And I'm being over melodramatic. The entire dance is set to a particular Taal and has to be followed with utmost precision. I cannot stress the importance of "Thaalam" or "Tala" (ताल ) in dance.